Police investigate Loop bank robbery

December 21, 2010 2:47:20 PM PST

December 21, 2010 (CHICAGO) --

Authorities are investigating a bank robbery that took place Tuesday morning in the Loop.

The Charter One bank at 71 South Wacker was hit just before 9 a.m. Police say the suspect presented the teller a note demanding money and implied he had a weapon. He then fled on foot with an unknown amount of cash.